[PATCH] drm/ttm: revert "make TT creation purely optional v3"

[Christian König]

Am 11.08.20 um 11:24 schrieb Christian König:
> This reverts commit 2ddef17678bc2ea1d20517dd2b4ed4aa967ffa8b.
>
> As it turned out VMWGFX needs a much wider audit to fix this.
>
> Signed-off-by: Christian König <christian.koenig at amd.com>

Dare to give me an rb for this? I already tested on amdgpu and it should 
be fixing the VMWGFX problems we currently have.

Thanks,
Christian.

> ---
>   drivers/gpu/drm/ttm/ttm_bo.c      | 19 ++++++++++++++++---
>   drivers/gpu/drm/ttm/ttm_bo_util.c |  7 ++-----
>   drivers/gpu/drm/ttm/ttm_bo_vm.c   |  5 -----
>   drivers/gpu/drm/ttm/ttm_tt.c      |  1 +
>   4 files changed, 19 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index ad09329b62d3..42386bda32fe 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -656,7 +656,7 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo,
>   		ttm_bo_wait(bo, false, false);
>   
>   		ttm_bo_cleanup_memtype_use(bo);
> -		return 0;
> +		return ttm_tt_create(bo, false);
>   	}
>   
>   	evict_mem = bo->mem;
> @@ -1191,8 +1191,13 @@ int ttm_bo_validate(struct ttm_buffer_object *bo,
>   	/*
>   	 * Remove the backing store if no placement is given.
>   	 */
> -	if (!placement->num_placement && !placement->num_busy_placement)
> -		return ttm_bo_pipeline_gutting(bo);
> +	if (!placement->num_placement && !placement->num_busy_placement) {
> +		ret = ttm_bo_pipeline_gutting(bo);
> +		if (ret)
> +			return ret;
> +
> +		return ttm_tt_create(bo, false);
> +	}
>   
>   	/*
>   	 * Check whether we need to move buffer.
> @@ -1209,6 +1214,14 @@ int ttm_bo_validate(struct ttm_buffer_object *bo,
>   		ttm_flag_masked(&bo->mem.placement, new_flags,
>   				~TTM_PL_MASK_MEMTYPE);
>   	}
> +	/*
> +	 * We might need to add a TTM.
> +	 */
> +	if (bo->mem.mem_type == TTM_PL_SYSTEM && bo->ttm == NULL) {
> +		ret = ttm_tt_create(bo, true);
> +		if (ret)
> +			return ret;
> +	}
>   	return 0;
>   }
>   EXPORT_SYMBOL(ttm_bo_validate);
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
> index 496158acd5b9..76376dc71f25 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> @@ -531,15 +531,12 @@ static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo,
>   		.interruptible = false,
>   		.no_wait_gpu = false
>   	};
> -	struct ttm_tt *ttm;
> +	struct ttm_tt *ttm = bo->ttm;
>   	pgprot_t prot;
>   	int ret;
>   
> -	ret = ttm_tt_create(bo, true);
> -	if (ret)
> -		return ret;
> +	BUG_ON(!ttm);
>   
> -	ttm = bo->ttm;
>   	ret = ttm_tt_populate(ttm, &ctx);
>   	if (ret)
>   		return ret;
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> index ba2e8bd198ad..e90c5c806645 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
> @@ -347,11 +347,6 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
>   
>   		};
>   
> -		if (ttm_tt_create(bo, true)) {
> -			ret = VM_FAULT_OOM;
> -			goto out_io_unlock;
> -		}
> -
>   		ttm = bo->ttm;
>   		if (ttm_tt_populate(bo->ttm, &ctx)) {
>   			ret = VM_FAULT_OOM;
> diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
> index bdd6169cef13..05c9147ac6d3 100644
> --- a/drivers/gpu/drm/ttm/ttm_tt.c
> +++ b/drivers/gpu/drm/ttm/ttm_tt.c
> @@ -70,6 +70,7 @@ int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc)
>   		page_flags |= TTM_PAGE_FLAG_SG;
>   		break;
>   	default:
> +		bo->ttm = NULL;
>   		pr_err("Illegal buffer object type\n");
>   		return -EINVAL;
>   	}